Electric and hybrid vehicles have recently become a more common sight on roads worldwide. They have one thing in common and that is they all require a large and powerful rechargeable battery. Despite the size of such batteries mounted in e.g. electric vehicles, they need to be recharged almost every day, depending on how frequently and how far the vehicle is driven.
The power required from a power source in order to recharge a rechargeable battery of an electric vehicle is substantial. A concern is the risk of a highly resistive point or connection such as e.g. a faulty connection, a broken cable or a loose connection somewhere along the electrical path from the power supply to the energy storage device which may be a hazard for a charging system. An increased electrical resistance together with the high currents in the charging system causes an increase in temperature and may thus become a fire hazard, or may damage components of the charging system. Furthermore, an increased electrical resistance of e.g. a charging cable may cause the power supply to saturate its output which puts unnecessary strain on the power supply.
For conventional charging systems there is commonly a dedicated cable with an integrated temperature sensor for detecting an increased temperature. A charging cable comprising a temperature sensor is disclosed in e.g. US2011/0204849. In the cable disclosed in US2011/0204849 a temperature sensor measures the temperature in the cable at, e.g. an end of the cable close to a power outlet.
However, such cables involve high complexity and are relatively expensive. Furthermore, an increased resistance may be due to e.g. heating of components such as cables of the system other than the charging cable, or any other highly resistive connection or defect. Such a defect (or heating or connection) may be present anywhere along an electrical path from a power supply to a battery and may thus be difficult to accurately detect with a temperature sensor integrated in the cable. Therefore, it is desirable to more accurately ensure a safe charging process.